In this paper the spectroscopic and the geometric properties of four ligands with pyrazole unit are studied at both experimental and computational levels.The computational results are perfectly in good agreement with ...In this paper the spectroscopic and the geometric properties of four ligands with pyrazole unit are studied at both experimental and computational levels.The computational results are perfectly in good agreement with the experimental results especially in terms of the IR,1 H-NMR and 13 C-NMR shifts.The spectroscopic features as well as the computed properties help to establish the successful synthesis of ligands bdmpzm and bdmpza.The theoretical and the experimental IR and Raman significantly help in distinguishing the four ligands.The results show that the Raman spectral is better applicable in characterising the CH3deformation,the C-H,CNN and CCNNout of the ligands but vibrations like N-H in dmpz and O-H,CO in bdmpza are observed to be Raman inactive.A significant variations are observed among the two available*N atoms characterising the bidentate features of bdmpzm,bdmpza and bdcpzm which indicates a possible different affinities for metal coordination.Also the result suggest that bdmpza will be the best starting material for NLO application than other while bdcpzm is predicted to have potential of been a poor coordinating ligand.The computed variations in the properties of*N atoms that are the characteristic features of their power of coordination can be of immense help since these type of ligands have a wide application in transition metal coordination.展开更多
The novel calixcrowns with two pendant groups were prepared by the alkylation of calixcrowns with 6-methoxy-2-bromoacetylnaphthalene. 1H NMR titration and picrate extraction experiments indicated that they exhibi...The novel calixcrowns with two pendant groups were prepared by the alkylation of calixcrowns with 6-methoxy-2-bromoacetylnaphthalene. 1H NMR titration and picrate extraction experiments indicated that they exhibit higher complexing efficiency than their parent compounds and possess obvious selectivity for Na + or K +, respetively, and that the cation is encapsulated inside the preorganized ionophoric cavity defined by carbonyl oxygens, the crown ether and the phenoxy oxygens. From UV and fluorescent spectra it is revealed that calix-crown-4 3a with 6-methoxy-2-naphthoylmethyl pedant groups exhibits remarkable cation-induced photophysical effects and it could be utilized as a selective fluorescent sensor for Ca 2+ .展开更多
A novel Schiff base (TAMET) was synthesized by the condensation of tetraglycol aldehyde with methionine and a mild oxidant CrO3. (C5H5N)2 was selected for the reaction. Seven new rare earth complexes with this Schiff ...A novel Schiff base (TAMET) was synthesized by the condensation of tetraglycol aldehyde with methionine and a mild oxidant CrO3. (C5H5N)2 was selected for the reaction. Seven new rare earth complexes with this Schiff base have been synthesized and characterized by elemental analysis, TG-DTA, molar Conductivity, magnetic susceptibility and IR, especially 1H NMR spectra. Information was obtained from reflectance spectra and the coordination of sulfur atom to rare earths was discussed. The experimental results show that these compounds have some biological activity and could dispose of O2?-.展开更多
Two new coenzyme B12 analogues, 2',5'-dideoxycytidylcobalamin (2a) and 2',5'-dide-oxyuridinylcobalamin (2b), and two others, 2',5'-dideoxyadenosylcobalamin (2c), and 5'-deoxy-thymidylcobala...Two new coenzyme B12 analogues, 2',5'-dideoxycytidylcobalamin (2a) and 2',5'-dide-oxyuridinylcobalamin (2b), and two others, 2',5'-dideoxyadenosylcobalamin (2c), and 5'-deoxy-thymidylcobalamin (2d) were prepared by an improved method. All the four analogues were investigated by UV-vis and 2D 1H NMR spectroscopy. The comparisons and discussion about their spectroscopic properties were done.展开更多
基金financial support of Govan Mbeki Research and Development Centre,University of Fort Hare,South Africa
文摘In this paper the spectroscopic and the geometric properties of four ligands with pyrazole unit are studied at both experimental and computational levels.The computational results are perfectly in good agreement with the experimental results especially in terms of the IR,1 H-NMR and 13 C-NMR shifts.The spectroscopic features as well as the computed properties help to establish the successful synthesis of ligands bdmpzm and bdmpza.The theoretical and the experimental IR and Raman significantly help in distinguishing the four ligands.The results show that the Raman spectral is better applicable in characterising the CH3deformation,the C-H,CNN and CCNNout of the ligands but vibrations like N-H in dmpz and O-H,CO in bdmpza are observed to be Raman inactive.A significant variations are observed among the two available*N atoms characterising the bidentate features of bdmpzm,bdmpza and bdcpzm which indicates a possible different affinities for metal coordination.Also the result suggest that bdmpza will be the best starting material for NLO application than other while bdcpzm is predicted to have potential of been a poor coordinating ligand.The computed variations in the properties of*N atoms that are the characteristic features of their power of coordination can be of immense help since these type of ligands have a wide application in transition metal coordination.
基金ProjectsupportedbytheNationalNaturalScienceFoundationofChina (No .90 10 10 18)
文摘The novel calixcrowns with two pendant groups were prepared by the alkylation of calixcrowns with 6-methoxy-2-bromoacetylnaphthalene. 1H NMR titration and picrate extraction experiments indicated that they exhibit higher complexing efficiency than their parent compounds and possess obvious selectivity for Na + or K +, respetively, and that the cation is encapsulated inside the preorganized ionophoric cavity defined by carbonyl oxygens, the crown ether and the phenoxy oxygens. From UV and fluorescent spectra it is revealed that calix-crown-4 3a with 6-methoxy-2-naphthoylmethyl pedant groups exhibits remarkable cation-induced photophysical effects and it could be utilized as a selective fluorescent sensor for Ca 2+ .
基金Project supported by the National Natural Science Foundation of China (No. 29671026)the Natural Science Foundation of Zhejiang Province (No. 296062)the State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics (No. 971502)
文摘A novel Schiff base (TAMET) was synthesized by the condensation of tetraglycol aldehyde with methionine and a mild oxidant CrO3. (C5H5N)2 was selected for the reaction. Seven new rare earth complexes with this Schiff base have been synthesized and characterized by elemental analysis, TG-DTA, molar Conductivity, magnetic susceptibility and IR, especially 1H NMR spectra. Information was obtained from reflectance spectra and the coordination of sulfur atom to rare earths was discussed. The experimental results show that these compounds have some biological activity and could dispose of O2?-.
基金Project supported by the National Natural Science Foundation of China.
文摘Two new coenzyme B12 analogues, 2',5'-dideoxycytidylcobalamin (2a) and 2',5'-dide-oxyuridinylcobalamin (2b), and two others, 2',5'-dideoxyadenosylcobalamin (2c), and 5'-deoxy-thymidylcobalamin (2d) were prepared by an improved method. All the four analogues were investigated by UV-vis and 2D 1H NMR spectroscopy. The comparisons and discussion about their spectroscopic properties were done.
